Question

In the following reaction, how many moles of NaCN are required to react with 5 moles of Au?

Options:
A) 2.5 moles
B) 5 moles
C) 10 moles
D) 15 moles

Answer 1

The number of moles of NaCN required to react with 5 moles of Au is 10 moles. The answer is determined by applying the stoichiometric relationship from the implied reaction equation showing gold reacting with sodium cyanide.

Step-by-step explanation:

The question asks about the stoichiometry of a reaction involving gold (Au) and sodium cyanide (NaCN). To determine the number of moles of NaCN needed to react with 5 moles of Au, we need the balanced chemical equation of the reaction. Unfortunately, the provided examples do not directly show the reaction between Au and NaCN, which typically resembles the equation: 4 Au + 8 NaCN + O2 + 2 H2O → 4 Na[Au(CN)2] + 4 NaOH. This equation shows that 8 moles of NaCN are needed for every 4 moles of Au, which simplifies to a 2:1 ratio.

Therefore, to react with 5 moles of Au, we need 2 times that amount of NaCN, which is 10 moles.

The correct answer is C) 10 moles.